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Chapter 1, problem 71, tells us that a single molecule has a mass of 7 .31 times 10 to the negative 23 grams.
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It also tells us that the number of protons equals the number of neutrons in the nucleus of each element in this molecule.
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And it asks us to come up with a real molecule that could potentially have this mass.
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So, to solve this, we must first find.
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Out how many protons and neutrons this mass represents.
00:41
Remember that electrons are light enough that we don't consider them when calculating the mass of an atom.
00:48
Also remember that the mass of a proton equals the mass of a neutron and that they are both 1 .67 times 10 to the negative 24 grams.
01:00
So if we divide the mass of our molecule by the mass of a proton or a neutron because they're the same, we can find out how many of them we have.
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So again, the number is 1 .67 times 10 to the negative 24 grams.
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This gives us approximately 44 protons and neutrons...